{POJ}{2421}{Constructing Roads}{Prim}

基本MST思路

#include<iostream>
using namespace std;
#define MAX 10000
#define INF 999999
int g[MAX][MAX],visit[MAX],dist[MAX];
int nv,ne,sum;
int prim()
{
	int i,j,tmp,mark_pos,mark_min;
	sum = 0;
	for(i = 1;i<=nv;++i)
	{
		dist[i] = INF;
		visit[i] = 0;
	}
	dist[1] = 0;
	for(i=1;i<=nv;++i)
	{
		mark_min = INF;
		for(j=1;j<=nv;++j)
			if(!visit[j]&&mark_min>dist[j])
			{
				mark_min = dist[j];
				mark_pos = j;
			}
		visit[mark_pos] = 1;
		sum+=dist[mark_pos];
		for(j=1;j<=nv;++j)
			if(!visit[j]&&dist[j] > g[mark_pos][j])
				dist[j] = g[mark_pos][j];
	}
	return sum;
}
int main()
{
	int i,j,tmp,b,a;
	scanf("%d",&nv);
	for(i=1;i<=nv;++i)
		for(j=1;j<=nv;++j)
			scanf("%d",&g[i][j]);
	scanf("%d",&ne);
	for(i=1;i<=ne;++i)
	{
		scanf("%d%d",&a,&b);
		g[a][b] = g[b][a] = 0;
	}
	tmp = prim();
	printf("%d\n",tmp);